Labuschagne, Root disagree about catch

A contentious catch has provided the first notable row in an amicable Ashes series, prompting a mid-pitch debate between Joe Root and Marnus Labuschagne at Lord's and further public disagreement.

Concussion substitute Labuschagne's match-saving knock of 59, which helped Australia secure a draw on day five of the second Test, ended when Root claimed a low catch at 6.38pm (local time).

The soft signal was out.

Labuschagne started to walk off but turned and returned to the crease after studying footage of his dismissal on the big screen, certain it had touched the grass before being scooped up by Root.

Most members of Australia's dressing room also felt there was enough evidence for third umpire Joel Wilson to rule 'not out', as did former England captain Michael Vaughan and pace legend Michael Holding.

In sharp contrast, Root was certain it was a clean catch and held up his finger to signal out.

Labuschagne walked off shaking his head after exchanging words with Root.

"As a fielder sometimes you feel like you've caught it and that may have been the case," Labuschagne told reporters.

"But definitely when I saw it on replay, I was like; it looks like it bounced.

"I'm not an umpiring professional, so we'll leave it to them. I'm just disappointed to get out that way, to put us under a little bit of pressure."

Root didn't mince words when asked about the incident.

"I said I caught it," Root recalled.

"I'm an honest guy. I'm not going to try to cheat the game, regardless of the situation.

"It's quite disappointing when it's slowed down and people start questioning your integrity. We play the game in a certain way and that's the right way.

"You know if your fingers are underneath the ball, clearly felt that was the case ... they (slow-motion replays) always look worse than they are."

Test umpires routinely ask the third umpire to review low catches whenever they're uncertain but footage of such dismissals is rarely conclusive.

Captains in some series have made a pact, agreeing to take the fielder's word on disputed catches.

"It'd be nice if there was a little bit more of that but it is what it is," Root said.

"DRS and everything - a lot more does go upstairs. It happens with catches as well.

"It's not going to change ... might as well just get on with it."

Counterpart Tim Paine tried to be diplomatic when asked about the divisive dismissal.

"He thought he caught it. You can make your own opinions from what you saw on the TV, I am not going to comment on it," Paine said.